ggmap

ggmap makes it easy to retrieve raster map tiles from popular online mapping services like google maps, open street maps, cloudmade and stamen:

library(ggmap)

(map <- get_map("pat neff hall", zoom = 15))
#> 1280x1280 terrain map image from Google Maps.  see ?ggmap to plot it.
ggmap(map)

(extent <- bb2bbox(attr(map, "bb")))
#>      left    bottom     right       top 
#> -97.13503  31.53403 -97.10756  31.55743
ggmap(get_stamenmap(extent, zoom = 15))

ggmap(get_stamenmap(extent, zoom = 15, maptype = "toner-background"))

Use qmplot() in the same way you'd use qplot(), but with a map automatically added in the background:

downtown <- subset(crime,
  -95.39681 <= lon & lon <= -95.34188 &
   29.73631 <= lat & lat <=  29.78400
)

qmplot(lon, lat, data = downtown, maptype = "toner-background", color = I("red"))

qmplot(lon, lat, data = downtown, maptype = "toner-lite", geom = "density2d", color = I("red"))

Installation

• From CRAN: install.packages("ggmap")

• From Github: devtools::install_github("dkahle/ggmap")